In recent years, technical barriers of three-dimensional (3D) display technology have been gradually broken through, and applications such as 3D movies and 3D televisions start to be presented to the market. The 3D effect brought by a 3D display is actually resulted from simultaneously presenting a left-eye image and a right-eye image corresponding to different viewing angles to an observer's eyes individually and independently, wherein depth of field resulted from a distance between two eyes when viewing the 3D display can be simulated by using the left-eye image and the right-eye image.
Autostereoscopic display technology is a newly developed technology for 3D display. Through the autostereoscopic display technology, a 3D image effect can be directly observed by naked eyes without wearing special 3D glasses. Conventional autostereoscopic display technology can be classified into three types in accordance with the methods used for generating multiple views. One type is time-multiplexing achieved by sequentially turning on a plurality of light sources. Another type is spatial-multiplexing achieved by dividing a pixel into a plurality of separate blocks for different multiple viewing angles. Further, another type is a multi-projector achieved by using a plurality of light modulators.
Wherein, the spatial-multiplexing is to insert at least two images of different viewing angles among pixels, such that each specific observing region can only view an image of a corresponding viewing angle.
In other words, the spatial-multiplexing achieves an autostereoscopic display effect of multiple viewing angles with sacrificing image resolution. The more the corresponding viewing angles are, the severer the resolution decrease is. When the 3D display is used to display a common two-dimension (2D) image, the resolution of the 2D image is also sacrificed. Therefore, those who are in this filed provide an autostereoscopic display technology with switchable 3D/2D display modes, and contemplate how to avoiding sacrificing resolution when the 3D display mode is switched to the 2D display mode.
In a conventional 3D/2D switchable display device, a mechanical method is mainly used to remove a lenticular lens film necessary in a 3D image formation process, so as to switch the display device from the 3D display mode to the 2D display mode. The conventional lenticular lens film is usually attached on a display panel and has a fragile structure, such that the conventional lenticular lens film is easily subject to damages caused by the aforementioned mechanically switching method.
U.S. Pat. No. 5,500,765 provides a 3D/2D switchable display device having a removable flip cover, and a complementary lens structure for the lenticular lens is disposed on the removable flip cover, so that a user can move the removable flip cover in a mechanical or manual manner to switch 3D/2D display modes. However, the removable flip cover and the lenticular lens have to be exposed to environment, and are subject to damages caused by hit, shock, and variation of temperature.
Another conventional 3D/2D switchable display device is enabled by using an electro-optical media material with an electronic switching method. For example, in U.S. Pat. No. 5,500,765, an electro-optical media material is filled between the lenticular lens and a planar lens, and different operation voltages are applied on an electrode of the electro-optical media material to vary an alignment direction of molecules of the electro-optical media material for switching the 3D/2D display modes. However, how to fill the electro-optical media material between the lenticular lens and the planar lens in a display panel having a great area; and the switching stability and efficiency of the electro-optical media material are still a quest to be solved.
The conventional mechanical switching method needs to greatly shift the position of the lenticular lens, and thus the lenticular lens is easily subject to damages. The electronic switching method has the problems of manufacturing difficulties, switching stability and switching efficiency.